If you forget to assign a category to a post or a link, WordPress automatically assigns them to a default category. Here’s how to control those defaults.
WordPress » WordPress 2.7 » WP 2.7 Basic » WP 2.7 Categories
Currently we’re only covering installed versions of WordPress, but in future we’ll be adding tutorials on the hosted version at WordPress.com.
Videos are classified by WordPress 2.7 or 2.6 mostly because the admin screens look different, so if you don’t see a video on your topic, try looking in the other section or try the alphabetical listing.
KEY: 
You have WP 2.7 if your admin screen looks like this:
WordPress 2.7 
You have WP 2.6 if your admin screen looks like this:
WordPress 2.6 
Administrators Only 
Requires a Plug-in 
Recently Updated
Browser Issues
You have WP 2.7 if your admin screen looks like this:
Change the default categories for posts or links
You have WP 2.7 if your admin screen looks like this:
The hierarchy of post categories
Post categories in WordPress can have sub-categories, which in turn can have their own sub-categories, and so on. This hierarchical relationship has many uses – it also means that you don’t have to check off parent categories, because all children, grand-children, etc. are automatically included in the parent.
You have WP 2.7 if your admin screen looks like this:
Deleting categories
When you need to delete a category in WordPress, there are a couple of ways to do it, and some things to keep in mind.
You have WP 2.7 if your admin screen looks like this:
Adding link categories
Links can be grouped under various categories and there are two ways to add new link categories.
You have WP 2.7 if your admin screen looks like this:
View the most-used categories
If you’ve got a lot of post or link categories, there’s a hand way to view the most-used categories first, saving you a lot of repetitive scrolling and searching.
You have WP 2.7 if your admin screen looks like this:
Adding categories to existing posts
If you want to add more categories to an existing post, there are a couple of ways you can do it.
You have WP 2.7 if your admin screen looks like this:
Assigning a group of posts to a category
If you have a number of posts that need to be assigned to one or more categories in WordPress, you can easily do that in a couple of keystrokes.
You have WP 2.7 if your admin screen looks like this:
Changing category names
After setting up a category for your posts, you may change your mind and want a new name for that category. Here are a couple of ways to do that.
